JSmol/Rotation Speeds

JSmol is the default form of Jmol used in Proteopedia and FirstGlance in Jmol. JSmol is used here to mean the HTML5/Javascript (non Java) application working within a web browser (see Jmol has four forms). The "JS" in JSmol refers to JavaScript. As mentioned in JSmol Notes, JSmol is substantially slower than the Jmol Java applet. With the exception of performance speed, both forms of Jmol have identical capabilities.

Performance of JSmol depends on the underlying performance of the javascript in the browser being used. Therefore, choice of browser is important.

ConclusionsConclusions

Firefox outperforms all other popular browsers for smoothness and speed of rotation, and is therefore the recommended browser for websites that use JSmol such as Proteopedia and FirstGlance in Jmol.

Chrome, Edge and Opera rotate molecules in JSmol about half as smoothly as Firefox. That is, they generate about half the number of frames/second as Firefox, so their performance is two-fold slower.

Internet Explorer 11 gives unacceptably slow rotation of molecules in JSmol, with a performance about one-fifth that of Firefox.

Historical note: In 2014, Chrome outperformed Firefox. Changes in Chrome in 2015 reduced its performance for rotating molecules in JSmol. In December, 2015, a change in Chrome (first in version 47) made it unable to rotate molecules in JSmol satisfactorily. As the mouse moved, the molecule remained fixed until the mouse movement stopped, whereupon the molecule jumped to the final position in one step. Bob Hanson was able to work around the change in Chrome with a modification to JSmol, but frames/second are still poorer than they were in Chrome in 2014.

DataData

Tests below were done in FirstGlance in Jmol in the default HTML5 mode, using 7ahl, a single model with 22,778 atoms (which puts it in the largest 5% of entries in the PDB). Tests were done in a browser window approximately 1,400 x 900 pixels on a late 2014 MacBook Pro (2.2 GHz Intel Core i7 with 1600 MHz DDR3 RAM). With spinning on, the number of frames in 10 sec was counted and divided by 10 to get frames/second. Browsers were the versions current in December, 2015.

Frames/Second in Cartoon, Spacefill
Operating System	Firefox	Chrome	Internet Explorer 11	Edge	Opera
Windows 10			1.2, 1.1	2.6, 2,8	3.0, 3.8
Mac OS 10.10.5	≥ 6, ≥ 6	2, 4	n/a	n/a